Headspace guage

Discussion in 'Reloading' started by 340Shooter, Jan 20, 2011.

  1. 340Shooter

    340Shooter Well-Known Member

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    I have the Hornady headspace kit and looking for help on how to use it :)
    Never used one before and wondering if anyone else uses it and can provide some how-to's.

    Thanks
     
  2. MSLRHunter

    MSLRHunter Well-Known Member

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    Basically you will use the tool to measure the difference in a case that has been fired in your gun but not sized to a case that has been sized. You will find that the case that has been sized is smaller than the fired only case. So now you can adust your resizing die so that it is only moving the shoulder of a fired case back by about 2 thousandths
     

  3. sakoluvr

    sakoluvr Well-Known Member

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    That's all there is too it. get the propper collar to fit the shoulder of the brass you are measuring. It touches the datum line on the shoulder. With your calipers, you measure from the head of the brass, to that datum line.

    I like to measure unfired brass, 1x fired brass and 2x fired brass (all unsized) to see wher the shoulder ends up. It depends on how tight your chamber is. As stated, do a partial full length resize, bumping your shoulder back about .002". I like to do this starting with 2x fired brass. I feel that it gives a better blueprint of your chamber. The 1x fired brass gets neck sized only.
     
  4. sakoluvr

    sakoluvr Well-Known Member

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    BTW, you can even make a collar up, but simply finding some pistol brass that fits over your rifle brass and touches at or close to the datum line. Just put your calipers on the head of the upside down pistol brass and on the head of the rifle brass that you are measuring.
     
  5. 340Shooter

    340Shooter Well-Known Member

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    Thanks for the help. I have some Weatherby calibers, and not sure if they can be measured the same way with the double radius shoulder.
     
  6. trueblue

    trueblue Well-Known Member

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    Good advice.


     
  7. Trickymissfit

    Trickymissfit Well-Known Member

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    I've made a few sleeves to check Weatherby cases in the past. The idea is to draw up the case head in a cad program, and then find the flat part of the shoulder between the radiuses. That will give you the correct I.D. of the sleeve. Then all you need to do is turn one out of aluminum or brass that will clear the total length of the neck plus still seat on the shoulder. What caliber are you shooting?
    gary
     
  8. boomtube

    boomtube Well-Known Member

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    Since we are only making comparitive measurements (fired vs. sized) any part of the shoulder can serve as well as any other. It's ideal to use the center third of the shoulder but that's not critical.

    If you're shooting a bolt rifle you do not need to set the sized shoulders back passed the fired lengths. The fired cases have already shrunk back a thou or two.
     
  9. 340Shooter

    340Shooter Well-Known Member

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    I am assuming then I can just use the fired case to set the sizing die? Measure them, and then adjust the die.

    I load for the following Weatherby rounds

    .300
    .340
    .375
    .460
     
  10. boomtube

    boomtube Well-Known Member

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    "I am assuming then I can just use the fired case to set the sizing die? Measure them, and then adjust the die."

    Exactly. Fact is, FL sizing pushes the shoulder forward as it squeezes the body diameter down. All we need do is restore the sized shoulder to match the fired dimension and you will be able to chamber the round but will have minumum slop in the fit.

    Sizing this way, correctly, reduces case stretch to virtually zilch and head seperations will be rare. I have cases I've reloaded 6-10 times with no sign of a seperation. And I don't load mild.